Clinical study - Sein Néoadjuvant

Patients with an invasive breast cancer on neoadjuvant chemotherapy (with the exception of cT2cN0 tumors) are preselected before the surgical procedure. They are definitely included during the post-surgery visit following the analysis of the surgical specimen (only patients whose tumor did not achieve a complete pathological response are included).;Sequential plasma samples for ctDNA mutations analysis will be taken during the post-surgery visit (within 2-5 weeks after surgery) and every 6 months (+/- 1 month) thereafter for 5 years.;In case of relapse patients will be proposed to participate to an optional research program with a blood test for ctDNA assessment and biopsies from a metastasis (when these biopsies are clinically indicated).